1. Field of the Invention
The invention relates to a directional separator-coupler circuit for medium-frequency carrier currents on an electrical line of the low-voltage alternating network.
2. The Prior Art
The transmission of information on networks for distribution and supply of low-voltage electrical energy is currently carried out by means of transmitter-receiver circuits with carrier currents E, which are coupled to the network, as represented in FIG. 1a, by means of a separator-coupler circuit D, so as to provide maximum coupling to the low-voltage network and minimum disturbance both to the network itself, called upstream network, and to the downstream network, most often consisting of the power supply installation of a subscriber customer. This type of coupler separator circuit must, on the one hand, provide matching of the transmitter-receiver circuit E, and, on the other hand, decoupling between the upstream network and the downstream network. For this purpose, a voltage coupling, by means of a transmitter coupling transformer, has been used up until now as separator-coupler circuit, as represented in FIG. 1b; the low-voltage circuits with carrier currents being thus completely separated galvanically. Such circuits give satisfaction from the point of view of decoupling of direct or homopolar current, but they do not make it possible, however, to produce a true directional coupler circuit.